Systems for hemming the edges two or more metal components together to form a part are well known. Such systems are commonly used in the manufacture of various automotive body parts, such as doors, lift gates, hoods, etc., as well as in the manufacture of a variety of other manufactured goods.
When, for example, an automobile door is to be fabricated in a prior art hemming press, a previously stamped outer door panel is loaded onto an appropriately shaped anvil and the previously stamped inner door member is then placed atop the inside of the outer door panel and is held in place, with a clamp or other suitable mechanism, with the edges of the outer door panel and the inner door member overlying each other. The hemming press is then activated, moving an appropriately shaped first hemming beam through a complex motion, over and onto the anvil, to fold the edges of the outer door panel and inner door member over onto each other to a first extent, typically about forty-five degrees.
The first hemming beam is then removed and a second appropriately shaped hemming beam is then moved through another complex motion, over and onto the anvil, to complete the hem by further folding the edges of the outer door panel and inner door member over onto each other to complete the part.
While hemming provides numerous advantages compared to other joining techniques such as welding, hemming does suffer from some disadvantages. In particular, the setup positioning and alignment of the anvil, clamp and hemming beams and the setup of the shape and range of movements of these parts of the hemming machine are time consuming to accomplish and these actions must be performed each time it is desired to setup the machine to hem a different part. Thus, to be cost and/or time effective, a large run of parts needs to be hemmed during a run to amortize the setup costs for the hemming machine for that part. Therefore, hemming operations are not generally susceptible to versatile and/or just in time manufacturing processes.
Further, the complex movement of the hemming beams, which move over and onto the components on the anvil to perform the initial hemming operation, and again to perform the second hemming operation to complete the part, results in a relatively long minimum cycle time for the hemming process.
It is desired to have a hemming system and/or method which allows for the relatively efficient change over of the system and method to hem different parts and which provides for a relatively short minimum cycle time.